Heating or heating cables with automatic regulation have a very wide application as one of the protective measures against icing of various objects, buildings and structures. Modern options have several advantages, including a simple and convenient installation method, as well as the ability to use segments of the required length. That is why many owners of private country houses are interested in what is a self-regulating heating cable.
General description of the product and installation
One of the most important parameters can be considered operational safety. The use of cables of the required length allows you to fully realize this quality. For example, for heating small terrariums, rather short options with a length of 20 cm are used.
In addition, using a special tee system, you can organize connections from several such products. The selection of the optimal length depends on the purpose of use. Experts advise selecting a heating cable with a margin if it is unregulated, otherwise its use may be completely impractical. Excess length is also a problem, since randomly distributed “extra” segments or winding loops leads to the possibility of accidental fire.
In general, there are several relevant types of such cables on the market, each of which has both certain advantages and a number of disadvantages. When choosing, you should focus on what the purchased product will be used for.
Primary Function and Applications
Heating cables are considered special products. As the main function, it is necessary to single out the conversion of electrical energy into thermal energy over fairly significant distances. The range of heat transfer depends, of course, on the length of the product and can reach from a couple of meters to several kilometers. These products form the basis of all cable heating and anti-icing systems.
In the domestic and industrial fields, such devices solve a number of problems, among which the following should be noted:
- creation of an electric underfloor heating system for heating residential and industrial premises;
- prevention of condensate formations;
- the ability to compensate for heat loss in tanks or pipes;
- building an effective anti-icing system for gutters, roofs or gutters;
- heating of various platforms in the open air, for example, zones for landing helicopters, stairs and steps on them, as well as ramps;
- support of technological processes in production by maintaining operating temperatures or using in heating and cooling modes according to certain algorithms.
During installation, the importance of these characteristics must not be underestimated. For example, exceeding the length allowed in the specifications of the chain often leads to premature failure of the heating sections.
Main characteristics
By and large, there are four main characteristics that you should rely on when choosing a product in a store. Their listing can be seen further:
- Linear power. The accepted standard unit of measurement is watts per meter, but manufacturers from North America often indicate this parameter in watts per foot length. The most common and popular models have linear power in the range from 10 to 60 W / m.
- The highest temperature is idle. This parameter of the heating cable means the value at which it can be without connecting to the network. The specification usually mentions that during the entire operational period in such a state the product is able to withstand no more than 1,000 operating hours.
- The maximum chain length. It implies the largest possible length of each of the sections that make up the branched system. In this case, the parameter does not change even in the case of using one segment. It is caused by a direct dependence on the thickness of the wires through which the current is supplied.
- The highest temperature in the load. With this value, the cable is able to work for quite a long time and not get any damage.
During installation, the importance of these characteristics must not be underestimated. For example, exceeding the length allowed in the specifications of the chain often leads to premature failure of the heating sections.
Resistive cables
They appeared first and have already begun to gradually give way to more advanced variants of such products on the market. Nevertheless, there remain the choice of many who need to purchase a simple heating cable for pipes at an affordable price. For all subspecies, the same basic characteristics are relevant. However, it is not recommended to save even more and cut existing pieces of cable into several sections.
This action will lead to a decrease in resistance and, as a result, exceeding the permissible maximum temperatures during operation. In this case, the chain will soon simply overheat and break. In addition to the relative cheapness, a number of other advantages of resistive cables can be cited, including their high degree of reliability, ease of installation, and simplicity of the device as a whole.
Actual subspecies in this case are three variations:
- Single core cables. They are considered the simplest and do not require the involvement of specialists for installation. The outer shell is thermally stable, and under it is a copper shielding braid. Next is an insulating layer that protects the core that conducts current from overheating. With the help of such products closed circuits are created.
- Two-core cables. Completely similar to the previous ones. Nevertheless, they already have a pair of cores as the main structure. If there is no need to create a closed loop in combination with a limited budget, this option would be an ideal choice.
- Zone cables. The structure is fully preserved, but is being improved due to the presence of spirals between the veins. Thus, heating occurs evenly, which eliminates the main disadvantages of heating cables of a resistive type.
Self-regulating cables
A more progressive and modern option. The main difference is the presence of a self-regulating matrix, which is made of an elastic semiconductor material and is located between the veins. The amount of power used and the efficiency during heating depend on the resistance level of the “smart” matrix, which determines the appropriate value according to the ambient temperature. For example, if one of the sections lies in ice and the other is in the air, then the cable can determine this. So the colder section will get more heat.
Among the positive qualities of such products, a number of the following can be distinguished:
- Flexibility and elasticity. Largely due to this, self-regulating heating cables for pipes have gained such wide popularity in the market: heating of surfaces with any shapes is available.
- Energy Efficiency. Separate heating of sections allows you to take exactly as much of it as is necessary under given conditions.
- Free cutting. Power and performance are independent of length. Any values are allowed.
- Relative ease of installation. Unlike resistive models, it is possible to lay parts of the cable on top of each other without harming it.
Installation tips and features
Experts and masters highlight a number of simple and effective recommendations that will help you do the work yourself, efficiently and in a short time. Before you connect the heating cable, you should settle in a favorable thermal zone, if possible. Of course, in outdoor conditions this is far from always feasible, however, at temperatures from -5 ° C and below, installation cannot be done due to the technical limitations of the product itself. The fact is that the special polymer structure inside the cores does not imply its initial laying in the off state under similar conditions.
However, one should not despair, because how to install the heating cable in the cold is still not difficult. At temperatures below zero degrees, the product loses its flexibility. You can avoid this effect if you carefully unwind the bay, and then turn on the product for one minute or a little longer. When heated, the flexibility indicators will be fully restored, which will allow for further installation work.
Also, do not plug in a cable that has not been previously unwound. In addition, when laying resistive cables in a place where sunlight will constantly fall on them, it is best to choose black products that are resistant to ultraviolet radiation.
External installation on the pipeline
In this embodiment, the wire will be fixed on the outer surface along the pipes or wound on them. In the first case, the installation is very simple in-house. Previously, on the one hand, the product is fixed by means of fiberglass self-adhesive or special heat-resistant plastic clamps. It is recommended to observe an interval of about 30 cm. It is worth remembering that the length of the heating cable for pipes is calculated by the length of the surface on which it will be mounted. In no case can you use metal mounts, because they can become excessively hot during use of the product.
The second way of fixing is intended mainly for pipes buried in the ground. The cable will be located at a certain offset, but not in a certain upper or lower part. This option is often called the "position of eight (four) hours." There is also another way to mount a heating cable for the pipeline - spiral. This ensures the best contact of the working surface with the product, however, this significantly increases the length of the material, and accordingly the total cost of the whole undertaking.
The pitch between the turns is adjusted taking into account the operating conditions. For the maximum possible heating of the surface, this interval should be as small as possible. This approach will be relevant in areas subject to the most severe freezing.
Internal installation in the pipeline
It is far from being possible to locate the heating cable inside the pipe in every case. The minimum cross-section of the water supply should be at least 40 mm, otherwise the water flow will simply partially overlap. It is worth noting that this method is definitely more complicated than the one described above, however, for relatively short sections of several meters, the best option is not easy to choose. Experts advise pulling such a cable from top to bottom, that is, through vertical sections. A number of additional equipment will also be required, including the required number of tees and sealing sleeves to connect the sections and eliminate cord slipping.
Most often, inside the pipe, the heating cable for the water supply is carried out only in certain situations where its use is more appropriate. These include repair or replacement of system elements. If the finished product is considered, then you can also insert and connect it yourself, without involving third-party specialists. However, assembling such a system is already more difficult. During installation, it is recommended to take into account a number of important factors and limitations. For example, you should not let wires through the locking valves or any other locking equipment so as not to cause significant damage during operation.
Cable installation for underfloor heating
In this scenario, particular attention should be paid to proper prior planning. It all starts with the question of whether the heating cable for the floor will be used as the main and only system or whether its role will be limited only to auxiliary to the main heating. In case of partial heating, it is enough to observe the minimum percentage of the surface to be covered, which usually depends on the type of room.
The following options can be cited as an example:
- residential premises - 60-70%;
- cuisine - 35-40%;
- toilet — 30%;
- Bathroom - 60%.
Installation of a warm floor, as a rule, is done in a screed under the tile. First of all, the place where the thermostat will be located is selected. The thermal insulation coating itself is mounted if the slope of the floor level does not exceed one centimeter over the entire area of the room. This fact is checked using an ordinary water level or level. The heat-insulating surface is fixed using a metal mesh, which, in turn, is fixed with plastic clips to the cable itself.
The cold section of the heating element is inserted into the installation box, while bending or deformation in this area is not allowed. It should also be remembered that the junction of the cold clutch with the heating part should be in the floor, and not on the wall gate.
Cable installation for a drainage system
Many resort to the use of such products due to the fact that ice often forms in drain funnels. This, in turn, becomes an obstacle to the flow of melt water from the roof surface. For pipes with a diameter of up to 10 cm, experts advise to conduct one string of wire, and with a larger diameter up to 30 cm, it is better to conduct two at once. Fastening is carried out using ordinary steel brackets. There is also advice according to which it is necessary to create a more powerful heating in the upper and lower parts of the pipe. You can do it by laying additional threads, for example, in the so-called “dripping” form or through several turns in a spiral.
In addition, with especially long pipes of three meters or more, the cable is lowered and secured using a special cable or chain with fasteners. It is enough to screw a hook or a metal rod into the wooden elements of the roof and fix it on the gutter. After the chain or cable is suspended behind it. It is also worth mentioning that the wound way of fixing the heating cable for the drain is no less relevant. It is best to combine it with pipes of medium or large diameter.